Novel artificial silk effects and process of producing same



Patented Apr. 23, 1935 NOVEL ARTIFICIAL SILK EFFECTS AND PROCESS OF PRODUCING SAlVIE Georges Heberlein, Wattwil, Switzerland, assignor to Heberlein Patent Corporation, New York, N. Y., a corporation of New York No lirawin Application May 18, 1929, Serial No. 364,338. In Germany January 15, 1926 Claims.

5 altered in one or more respects, such as a change in the characteristic appearance and/or hand (touch). I use the term artificial silk in this specification and in the appended claims as designating the various forms of regenerated cellulose such for example as artificial silks known as viscose, cuprammonium and nitro cellulose silks, the latter being exemplified, for example, by those known in commerce as Chardonnet & Tubize; and as excluding acetate silk.

According to the invention, for example, artificial silk (regenerated'cellulose butnot acetate silk) may be so treated that the characteristic excessive lustre of artificial silk fabrics will partially or wholly disappear and the fabric will assume a lustreless, transparent effect, and become stiffer to the touch. As will be more fully explained according to this invention, a variety of novel effects in artificial silk may be obtained, and some of -these effects are especially. valuable in the production of pattern effects on fabrics made entirely or partly of artificial silk fibres.

The process is applicable to artificial silk goods whether in the form of yarn (threads) or fabric (in the piece), and whether the thread or the fabric is made entirely or only partly of artificial silk.

This is a continuation in part of application Ser. No. 161,022 filed January 13, 1927. The claims in the basic or parent caseare directed broadly and specifically to a processfor treatment of artificial silk to modify or eliminate the high lustre and to produce increased stiffness and translucency in conjunction with the reduced lustre. Claims are also included for the use of alkali hydroxide for a swelling agent in the process. Product claims are also included. The present case includes both product and process claims and is directed particularly to artificial silk which has been equalized and to a process for causing such equalization. It 'also includes claims for. the use of sulphuric acid or other mineral acid for this purpose.

The enobling of cotton fibres by means of swelling agents is known. It is possible thereby to impart upon the fibre a lustrous appearance by mercerization and to produce thereon transparent and/or woollike effects by means of concentrated acids, according to conditions. When cellulosic material such for example as natural cotton fibres or regenerated cellulose is acted upon by a swellingagent the swelling action or the structural change brought about in the fibre is dependent upon certain factors, 1. e., concentration of the swelling agent and time of treatment, and with most swelling agents upon the temperature 5 of the agent, as is now well known. If the concentration is too low the swelling action will not take place in a given fibre, no matter how prolonged the time of treatment may be, and also if the concentration is sufficient to produce the de- 10 sired effect on a particular fibre when applied for a sufficient time, if not applied for a sufiicient time there will be no or'substantially no swelling action. Likewise utilizing a suitable concentration for the desired effect on a particular fibre, if the time of treatment is too long the particular fibre may be destroyed or spoiled. As is also now understood, variations in temperature of most of. the swelling agents permit of variations in one or both of the other factors-concentration and time of treatment.

The degree of capability of a swelling treatment to attack or alter cellulose fibres, I will designate for brevity and convenience herein as the severity of treatment. For example, if sulphurio acid of say 54 B. is allowed to act at a given temperature upon a previously mercerized cotton'fabric for say 5 seconds, and a certain swelling action is obtained, the severity of such treatment will be less than one utilizing the sulphuric acid at a concentration of 58 B. and at the same temperature for the same duration; the severity of treatment being measured by the extent to which the fibres are attacked by the treatment.

Now I have discoveredthat swelling treatments which are of suitable severity? for producing desirable swelling actions on natural cotton fibre or fabric, are too severe for the treatment of arti- I ficial silk (regenerated cellulose) and will destroy 40 the same, but that such artificial silk can be successfully treated with swelling agents to produce various desirable permanent effects provided the severity of treatment with the swelling agent is less than that capable of producing any or any substantial swelling action on the ordinary or natural cotton fibre or fabric.

While it is impossible to specify the exact factors, i. e., concentration, time of treatment and temperature, for every desired effect on the artificial silk, due to the numerous variety of effects that may be desired and the various conditions under which the artificial silk is to be treated, nevertheless, in view of the foregoing general rule taken in connection with the specific examples of treatments and other information hereinafter given, those skilled in the art will be able to determine the swelling agent and the desired factors of time, concentration and temperature for the treatment of any particular artificial silk (regenerated cellulose) for a particular finish or effect.

According to this invention valuable changes on artificial silk can be produced by means of swelling agents, whereby novel characteristics, not known before on artificial fibres, are obtained. Such swelling agents are: Alkali-hydroxide of concentrations as generally used for mercerizatiomi. e". of a density of above 10 .B. sulphuric acid of a density of above 42 Be. phosphoric acid of a density of above 50 B. muriatic acid of a density of above 20 Be. nitric acid of a density of above 35 B. as well as mixtures of the above-mentioned acids; concentrated salt solutions, i. e. chloride of zinc solution of a density of above 50 B. calciumrhodanic solutionof a density of above 25 B copperoxydeammonia solution with at least 0.3% copper content; but from the commercial standpoint the most desirable of these swelling agents for treatins artificial silk. are,-caustic soda, sulphuric acid, nitric acid and the nitration acid mixtures. Additional substances as proposed for the mitigation of the reaction can also be added to these agents; among which substances are included one and more univalent and multivalent alcohols heterocyclic bases, formaldehyde and ammonia salts.

In treating artificial silk during longer or shorter periods according to tion of the swelling agents, and in conformity with the prevailing operating temperatures, the same loses a part of its excessive lustre and quite in contrast to the reflection of light which is otherwise predominant above everything else, it becomes transparent or translucent; and gradually an effect develops similar to the known transparent or glass like batiste efiects on cotton. If desired by means of variations in the concentration temperature and time of action any intermediate grade. between the high lustrous character of the original material and the dull, glasslike transparent, stiff, final product can be obtained.

By such treatments the artificial silk obtains new characteristics unknown before. It has been discovered that just at the beginning of the action, when no extensive swelling has taken place, and hence almost the full lustre is still present, especially in fabrics of artificial silk, an unexpected equalization of the fabric structure takes place, thus causing the unpleasant stripes, which very often appear in artificial silk to disappear. Also if the swelling of the artificial silk is not continued beyond the permissible measure, then a remarkable increase of the tensile strength is observable; this is due to surface adhesion of the single fibres or filaments.

Each of the mentioned reagents alter artificial silk in a similar manner as above described; that is, they all act to increase the stiffness and translucency of the artificial silk fabric, and many of them to reduce or entirely eliminate the excessive lustre. But in the use of nitrating acid (a composition containing varying proportions of sulphuric and nitric acid with varying aqueous content) widely vary and different effects are produced depending upon the ratio of the nitric acid to the sulphuric acid and upon the aqueous content of the mixture.

the kind and concentra.

For example, if the nitrating acid has an aqueous content below 20%, then quite different effects are produced upon the artificial silk depending upon whether the nitric acid content or the sulphuric acid content predominates. For example if more nitric than sulphuric acid is present the result will be an entirely lustreless non-translucent product; whereas if the sulphuric acid predominates the result will be a voluminous soft rich lustre effect of crepe-like character more nearly like natural silk. But if the nitrating acid contains 20% or more water then regardless of whether thenitric or sulphuric acid predominates, the result is similar to that with the use of the other reagents, i. e., a diminishing of the high lustre and increased stiffness and transparency.

It will thus be seen that one may produce various effects by the use of different mixtures of sulphuric and nitric acids. Such nitrated products may be subsequently treated with known denitrating means to rid them of their ready inflammability.

The manipulation of artificial silk is mostly carried out at normal temperature, but also low temperatures can advantageously be employed, whereas in the use of salt solutions often the warming of agents, partially to above the boiling point of water, is necessary. The acting period can be from a few seconds to several minutes, according to the desired'eifect, in individual cases up toone hour. The fibre material is held loose or under tension in the swelling agents, depending upon the effect desired.

The process is applicable to all kinds of artificial silks of regenerated cellulose, but not to acetate silk. They may be treated loose, spun or woven or as a formation of any kind, alone or also mixed with other fibres. Also those fibres, designated as staple fibre, and products obtained by spinning of short single fibres, are

ennoblement.

Examples 1. Bleached artificial silk fabrics are passed through caustic .alkali of 20 B. for a period of 4 seconds at normal temperature and slight tension, washed out, scoured with diluted sulphuric acid, thoroughly washed and dried. The fabric becomes stiff, translucent, and still exhibits a faint lustre.

2. De-sized artificial silk is passed through a bath cooled to minus 10 C. of sulphuric acid of 49 36. during 5 seconds, washed completely free from acid and dried. The fabric becomes somewhat stifier, still shows a high lustre though slightly reduced, has become slightly translucent and appears much more uniform in structure; that is to say, the above-mentionedequalization of the fabric structure is apparent.

. 3. Immerse artificial silk fabrics at normal temperature during 5 minutes into nitric acid 01 40 34%. wash out well and dry. The fabric shows a high lustrous, translucent effect with considerable stifiness of the fabric.

4. Artificial silk yarn is impregnated for a period of 10 minutes in a nitrating acid mixture, consisting of 4 parts sulphuric acid and one part nitric acid with an aqueous content of 7%, then washed and dried. The fibre becomes voluminous, soft, and has acquired the rich lustre of real silk.

susceptible to this a nitrating acid mixture and 1 part sulperiod of 5 minutes in consisting of 5 parts nitric acid phuric acid with an aqueous content of 6%, then washed and dried. Thefibre becomes entirely lustreless and non-translucent.

6. Artificial silk fabrics are passed through a chloride of zinc solution of 67 B. at 40 C. during a period of 10 seconds, washed out and dried. The fabric has become translucent and has lost its lustre. Those skilled in the art will observe from a consideration of the foregoing five specific examples of treatments according to the present invention, that in each case 'the factors of concentration, temperature and duration of treatment are so chosen that the "severity of treatment is insufficient to produce any or any substantial swelling action on natural cotton fibres. Taking for illustration the treatment of Example 1,-while the caustic alkali is of ordinary mercerizing strength yet the period of treat ment is but four seconds at normal temperature as contrasted with the duration of treatment of from 8 to 12 seconds for mercerizing.

If the above named swelling agents are allowed to act upon localized portions of fabrics, which contain artificial silk, these portions are effected, producing contrast between treated and untreated portions, which is enhanced by dyeing due to different afiinities for certain dyes.

This fact can be of use for producing patterned efiects. The local action of the swelling means can be done by laying on the same directly, by printing, blowing or painting, with or without thickening means, reserves can be applied and the fibre material consequently immersed in the swelling means. Dyestuffs can be added to the reserves, by which a local color effect can be produced together with the reserve.

The process can be used on all kinds of material made of artificial fibres consisting of regenerated cellulose. Materials made of artificial silk mixed with natural vegetable and animal fibres can be thereby treated.

In treating mixed materials it has been discovered, that it is. advantageous for producing soft effects if the natural fibres, such for example as cotton, are worked up in the grey condition and are only cleaned or bleached after the local action of the swelling agents thereupon. By this means the end is attained that the natural fibres, in consequence of their natural incrustations, are not so quickly affected by the swelling agents, i. e., are not affected during the time required for altering the regenerated fibres, and therefore retain their original construction. If artificial fibres and both raw and already disintegrated natural fibres are employed side by side in mixed fibres, the variety of the effects is further increased, a result that makes itself evident particularly in subsequent dyeing.

Where in the appended claims I use the term artificial silk I wish to be understood as including regenerated cellulose in the form of fibres, threads or fabric, and whether or not, in the case of threads, they also contain cotton or other fibres; and whether or not, in the case of fabric, it also contains cotton or other threads. Also I wish to be understood by the term artificial silk fabric as used in the claims, to include fabrics made either wholly of regenerated cellulose fibres or of mixtures of same with other fibres.

Such features of my invention as to product 1 and process, not herein claimed, will be the subject of copending applications, Ser. Nos. 161,022 filed January 13, 1927, 364,335/6/7 each filed May 18, 1929.

The term mineral aci as usedin the claims is intended to include both nitric and sulphuric acids.

Having thus described my invention, what I claimas new and desire to secure by Letters Patent, is:

1. A process for producing a novel character of artificial silk which comprises subjecting artificial silk fabric to a swelling agent of a severity substantially incapable of swelling cotton but capable of substantially altering the characteristics such as the lustre, stiffness and translucency of the artificial silk, allowing the agent to commence such alteration but stopping the action of the agent before the lustre has been substantially aifected and when only a slight increase in translucency and stiffness has occurred and the fabric has assumed a substantially uniform appearance'without the unpleasant stripes usually associated with artificial silk.

2. A process for producing a novel character of artificial silk which comprises subjecting artificial silk fabric to a mineral acid of a severity substantially incapable of swelling cotton but capable of substantially altering the characteristics such as the lustre, stiffness and translucency of the artificial silk, allowing the agent to commence such alteration but stopping the action of the agent before the lustre has been substantially afiected and when only a slight increase in translucency and stiffness has occurred and the fabric has assumed a substantial- 1y unifonn appearance without the unpleasant stripes usually associated with artificial silk.

3. A process for producing a novel character of artificial silk which comprises subjecting artificial silk to a sulfuric acid of 49 B. of a severity substantially uncapable of swelling cotton but capable of substantially altering the characteristics such as the lustre, stiffness and translucency of the artificial silk, allowing the agent to commence such alterations but stopping the action of the agent before the lustre has been substantially affected and when only a slight increase in translucency and stiffness has occurred and the fabric has assumed a substantially uniform appearance without the unpleasant stripes usually associated with artificial silk.

4. A process for producing a novel character of artificial silk which comprises subjecting the artificial silk fabric to a bath of sulfuric acid of about 49 B. during five seconds at a temperature about --10 C. to cause a slight reduction in the lustre of the fibre and slightly increase translucency and. stiffness and the appearance of a more uniform structure without the unpleasant stripes usually occurring in artificial silk.

5. Artificial silk fabric having a somewhat greater stiffness and greater translucency than untreated artificial silk and possessing a more uniform structure substantially without the objectionable striped appearance usually occurring in artificial silk, formed by treating the artificial silk with sulphuric acid of a severity substantially incapable of swelling cotton, but capable of altering the characteristics of the silk to produce the effect mentioned.

GEORGES HEBERLEIN. 

